Remote control apparatus



Dec. 31, 1963 G. v. MoRRls 3,116,368

REMOTE CONTROL APPARATUS I 5 Sheets-Sheet 1 Filed Nov. 9, 1960v 4/ INVENTOR.,

@orge U. orrz De. 31, 1963 G.V.MORR1S 3,116,368

REMOTE CONTROL APPARATUS Filed Nov. 9, 1960 3 Sheets-Sheet 2 ON TROL TRANSMITTER -nnaz II :I Il (HASSIS MENTARY CLOSE RELAY lI Tv REGEIVERl/ ZI AUDIO AMPLIFIER 1 AND LOUD SPEAKER I I I I i Y I SUPPLY INVENTOR. George U, Worms Dec. 31, 1963 G. v. MORRIS 3,116,368

REMOTE CONTROL APPARATUS 5 Sheets-Sheet. 3

Filed Nov. 9. 1960 Ffa. 4f

59 NVFJvTolL George f2/oww United States Patent Oiilice 3,116,368 REE/IOW CONWL APPARATUS George V. Morris, Norridge, lll., assigner te Zenith Radio Corporation, a corporatinn et Delaware Filed Nov. 9, 196i?, Ser. No. 68,215 9 Claims. (Cl. 179-1) This invention relates to intelligence-reproducing apparatus such as radio and television receivers, phonographs and the like, and more particularly to such apparatus equipped for remote control.

The use of a remote control system for controlling the several operating characteristics of an intelligencereproducing device such as a television receiver is now a common practice in the art. The remote control system greatly enhances the convenience of operation of the device. For example, in the case of a television receiver, the user may tune to different channels, change volume, and perform many other functions from the convenience of his armchair. Adjustment of the audio volume level is one of the more complex functions to be controlled by the remote control system. The ideal volume control would give the user the ability to turn on the set; establish a nominal setting of volume while the set warms up so that when audio starts it can be heard; effect substantially step-less controlled increase in volume; provide instantaneous muting of audio from any volume setting; and operate the on-otf switch of the television receiver. However, as the number of controlled operating characteristics increases, the number of control channels in the remote control system is correspondingly increased, with an attendant increase in system cost and complexity. To provide enough control channels for independently controlling all of the abovenamed desirable volume control operating characteristics would obviously be possible only in a system so costly as to be commercially impractical. Consequently, prior remote control systems for television have combined other control functions such as on-off or mute with volume control, but no commercial practical prior system achieves all of the desiderata set forth above. For example, continuous volume controls utilizing two control channels have been constructed which turn the television receiver on and off and increase and decrease volume continuously, but the operating characteristic of instantaneous muting of the audio volume has been sacriced. Other devices have been used which utilize only one control channel and provide on-off and a step increase in volume only; here both instantaneous mute and continuous volume control are sacriced.

Accordingly, it is a principal object of this invention to provide a new and improved intelligence-reproducing apparatus adapted for remote control.

It is another object of this invention to provide a cornrnercially practical remote control system in which remote volume control is achieved with greatly increased versatility and with an economical number of control channels.

The present invention provides a remote control apparatus comprising a control device including an adjustable element having a reference position and a plurality of additional operating positions for controlling an operating characteristic of such apparatus. Electrically operated driving means are coupled to the control device for varying the adjustable element between its operating positions. Control-signal-responsive means are provided for energizing and de-energizing the driving means at will. Means independent of the driving means directly reset the adjustable element to its reference position from any of its additional operating positions. Finally, control signal responsive means are provided for actuating the resetting means.

CII

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:

FlGURE l is an elevational view, partly in section, of a switching device employed in a preferred embodiment of the invention;

FXGURE 2 is a partial sectional view taken substantially along line 2 2 of FIGURE l;

FIGURE 3 is a schematic diagram of a preferred embodiment of the invention; and

FIGURES 4, 5 and 6 are partial elevational views of FIGURE l useful in explaining the operation of the embodiment of FIGURE 3.

In FlGURE l, a driving motor l@ is coupled to a cam lll by a worm gear arrangement l2 which reduces the rotational speed of cam 1l in comparison to motor il). Cam l1 is mounted on a shaft la supported for rotation in a supporting plate i3 and includes two offset semi-circular cam surfaces 26 and 26 which engage a reciprocating lever ld, the clockwise rotary motion of cam il being translated by cam surfaces 26 and 26 to a reciprocating motion of lever ld. Lever la is pivoted on a pin 2S which is fixed to plate i3 and is held against cam ll by a tension spring l5. Reciprocating lever i4.- is pivotally coupled by a pin 29 to a ratchet arm 17 having an upwardly projecting stud Ztl and which is held against the teeth of a ratchet wheel i8 by a tension spring l?. Ratchet wheel l?, is mounted on a shaft 3@ supported for rotation in plate 13, and includes an upwardly progecting stud 2.1 fixed on the face of wheel l, and is biased by a helical spring 22 (shown in dashed outline) against rotation in a clockwise direction. A pawl 2.3 is rigidly coupled to a rocker arm 24 which is connected to a tension spring Z5 biasing rocker arm 261 and pawl 23 in a clockwise direction and forcing pawl Z3 against the teeth of ratchet wheel l@ thereby impeding counter-clockwise rotation of the ratchet wheel. Rocker arm 242- is pivotally mounted on a shaft 27 mounted for rotation in supporting plate i3 .and includes a hook-shaped extension 32 on one end adapted for engagement with stud 2l of ratchet wheel l (see FG. 2), an extension 33 adapted for engagement with stud Ztl of ratchet arm i7, and a bearing surface 34- which is in physical Contact with a plunger 35 of a solenoid 37. Actuation of solenoid 37 forces plunger 35 against bearing surface 34 causing a counter-clockwise movement of rocker arm 24 and pawl 23; pawl 23 is thus disengaged from ratchet wheel l and extension arm 33 intersects stud 2d moving arm 17 out of engagement with the teeth of ratchet wheel 18. The relation between hook-shaped extension 32 and stud 2l will be discussed later.

Referring to FGURE 2 which discloses some aspects of the device of FGURE l more clearly, ratchet wheel lll is mounted on shaft d@ which is seated in bearings 38 and 39 mounted on plate i3 and a plate extension 13' respectively. Spring 22 has one end fixed to shaft 30 and the other is fixed to supporting plate ld by a pin 3l. A disc d@ is mounted on the forward end of shaft Sti and includes an arcuate slot i2 (sce FIGURE l) in which is mounted an adjustable stud 4l. At the other end of shaft 3@ a movable contact or switch arm 43 is provided which engages a resistance printed on an insulating board 4d.

Also mounted on supporting plate i3 is a switch 47 (shown in FHS-URE l) which includes normally open flexible contacts or switch arms -ti and 4'?. Contact 49 includes a tip portion 59 adapted for engagement with stud 41 or disc and is engaged by stud 431 during rotation of ratchet wheel (see FIGURE 4) to close switch 47. Switches 52 and 53 (see FIGURE 1) are also mounted on supporting plate 13. Switch S2 includes normally open flexible contacts or switch arms 54 and 55, contact SS' including a tip portion 56. Switch 53 includes normally closed flexible contacts or switch arms 59 and 6i), switch arm e@ including a tip portion 61. A plate 63 is pivotally mounted on plate 13 by a pin 64 and includes a projection 65 adapted for engagement with stud 21 of ratchet wheel 13 as best shown in FIGURE 2 and 'a projection 66 which includes upwardly projecting studs 63 and 69 adapted for engagement with tip portions 56 and 61 respectively. The pivotal motion of plate 63 is limited by a slot 7d in the plate and a pin 71 which is xed to plate 13 and extends through slot 7d. Before lthe clockwise rotation of plate 63 is limited by pin 71, as shown in FIGURE l, stud 69 engages end portion 61, thus disengaging switch 6@ from contact with switch arm 59; before the counter-clockwise rotation of plate 63 is limited by pin 71, stud d engages end portion 66 making contact between switch arms 55 and 54.

Referring now to FIGURE 3, a conventional television receiver 72 adapted for remote volume control is shown as an example of a type of sound reproducing apparatus to which the present invention is particularly applicable. The switching device of FIGURE 1 is shown in its functional setting mounted on plate 13. The construction and operation of television receiver 72 may be entirely conventional except for the operation of the volume control which will be discussed below.

A control receiver 73 which detects remote control signals generated by an ultrasonic transmitter 74 includes a frequency-selective amplifier coupled to a microphone '75 for detecting ultrasonic control signals. Transmitter 74 may be of the type including longitudinal-mode vibrators such as aluminum rods and strikers which are operatively associated with each rod. When the user operates a striker, a rod is struck on its end and generates an ultrasonic control signal of a frequency determined by the physical length of the rod. By using several different rods of diirerent lengths, remote control signals of several distinctively diiierent frequencies may be selectively generated. In the illustrated embodiment of FIGURE 3, transmitter 74 selectively develops ultrasonic control signals of two distinctive frequencies. Individual control signals radiated by transmitter 74 are detected by control receiver 73 to develop control pulses on control channels 1 or 2, depending upon the frequency of the transmitted remote control signal. As thus far described, the remote control system may correspond to that described in U.S. Patent 2,817,025 granted to Robert Adler on December 17, 1957 and assigned to the same assignee as the present application.

Included in control channel 1 is a control tube 7'7 comprising a control grid 78 coupled to control receiver 73, a grounded cathode Si?, and a plate or anode 82 which is connected by a lead tsl-t to the actuating element of a bi-stable relay 555. Grid 78 is shunted to ground through a biasing battery 79 connected in series with a resistor 79. Similarly included in control channel 2 is a control tube S7 comprising a control grid 8S coupled to control receiver 73, a grounded cathode 9h, and a plate or anode 92 which is connected by a lead 94 to the actuating element of a momentary-close relay 93. Grid S3 is shunted to ground through a biasing battery 89 connected in series with a resistor S9. The actuating elements of both bistable relay 83 and momentary close-relay 93, and hence plates d2 and 92, are supplied B+ voltage from control receiver 73 by B+ leads 95 and 96 respectively.

A receiver power supply 98 of television receiver 72, as well as solenoid 37, driving motor 19, and control receiver 73 are all adapted to be energized from a conventional power plug 99. Switch 53 is in series with one of the energizing leads to receiver power supply 93, de-energizing the power supply when it is open and energizing the power supply when it is closed. The switch contactsl lltltl of bi-stable relay 83 are in series with the energizing; circuit to driving motor 1@ for energizing and dce-energizthe motor; also in series is a solenoid 102 which when energized closes a normally open switch 1113 connected in series with switch 47 to complete an alternate energizingcircuit for bistable relay 83. The switch contacts 1943- of momentary-close relay 93 are in series with the energiz ing circuit to solenoid 37, and the power supply leads to*x solenoid 3'7 also include a diode rectifier 108 and associated load circuit comprising resistance 167 and capacitor 165. When switch 11M is closed by actuation of relay 93, solenoid 37 is energized thus actuating plunger 35. However the opening of switch 164 does not immediately de-energize solenoid 37 since the energy stored in capacitor is dissipated through solenoid 37 thus delaying the release of plunger 35 for a time determined by the time constant RC of load circuit 107, 1135.

Switch arm 4t; (shown in dashed outline) of switch 47 is connected to lead 84 through switch 193; switch arm 49 is grounded. Switch arm 55 of switch 52 is connected by a lead 106 to lead S4 while switch arm 54 is terminated on ground.

Printed resistance board 44 is shown in television receiver '72 as a rheostat type resistance 44 having one terminal 169 which is grounded and the other terminal 110 which is connected to a previous audio amplifier stage of television receiver 72. Switch arm 43 is connected to an audio amplifier and loudspeaker 112 and as shown in FIGURE 2 is coupled to ratchet wheel 13. As arm 43 is moved from terminal 109 to 110, the portion of the signal voltage from the previous audio ampliler being applied to audio amplifier and loudspeaker 112 is increased thereby producing a higher audio volume level.

Since disc d@ is coupled to volume control 413, 44, itsrotational position isrlindicative of the audio volume level'A of television receiver 72. With switch arm 43 near ter-i minal 109, the audio volume is muted or at a zero level and the position of the volume control is indicated orrdisc 41B by the mute designation; this occurs when mute is opposite an index mark 114 which is placed orf a front portion 113 of television receiver '72. Higher levels of audio volume are indicated by the reference numbers 1-11, 11 being established opposite index mark 114 when switch arm 43 is near terminal 11d of resistance 44 for maximum volume.

In operation, it may be assumed that receiver power supply 98 of television receiver 72 is de-energiz'ed or ofi Receiver power supply 98 is tie-energized when, referring to FIGURE 1, ratchet wheel 1S is rotated in a counter-clockwise direction until stud 21 engages projection 65, rotating plate 63 clockwise and causing stud 69 to move against tip portion 61 to disengage movable contact 6d from contact 59 and open the energizing cir'- cuit to receiver power supply 98. The counterclockwise torsional force of spring 22 retains stud 21 against extension 65. With ratchet wheel 18 in its off position, as indicated by the o designation on disc 4t) of FIGURE 3 being located opposite index mark 114, switch arm 43 of volume control 43, 44ris in contact with ground terminal 109 of resistance 44.

When the user wishes to energize television receiver 72, he actuates transmitter 74 to produce a command signal of a frequency which causes control receiver 73 to develop a control pulse in control channel 1. The control pulse is positive and overcomes the negative bias of battery 79 causing control tube '77 to conduct, thereby grounding lead 341.1 and placing B+ across the actuating; element of relay 33. Actuation of lai-stable relay 831 closes switch 1% which in turn energizes driving motori 1d.

Referring to FIGURE l, driving motor 10 rotates cam' 11 clockwise, causing arm 17 to moveratchetwheel-18 in a clockwise direction. Since Contact arm d3 (FIG- URES 2 and 3) is also coupled to the saine shaft as ratchet wheel 1.3, it also rotates in a clockwise direction, gradually increasing the signal voltage to audio amplier and loudspeaker M2 thus increasing the audio volume level in a manner well known in the art. At the initiation of rotation of ratchet wheel l5, stud 2l is moved away from project-ion 65 allowing plate 63 to pivot in a counter-clockwise direction, being pivoted by the bending force of switch arrn all and tip portion el, thereby allowing switch 53 to return to its normally closed position and energizing receiver power supply @3. As ratchet arm 17 rotates ratchet wheel i8 in a clockwise direction against the bias of torsional spring 22, pawl 213 prevents any backward motion oi the ratchet wheel.

Ratchet wheel l continues to rotate clockwise until adjustable stud 4l engages tip portion 5e ot switch i7 forcing switch arm t9 into contact with switch arm It?. as shown in FEGURE 4. Meanwhile, and referring back to FGURE 3, the continued energization or" motor lil has energized solenoid ll closing switch 1.63. While switch lll?, is closed, the closing of switch 47 by stud 4l grounds lead lill to actuate lai-stable relay 53. Switch lil@ of relay 83 opens, de-energizin" motor it? and stopping the motion of ratchet wheel l@ at an intermediate audio volume level. ilthough stud il may still hold switch i7 in its closed condition, ground is removed from lead 34 'oy the opening or" switch 193 since de-energization of motor l@ also de-energizes solenoid 1h32. Thus, by means of switch t, lai-stable relay 85 is conditioned to operate into its closed position when lead Sf-lis again grounded.

The relative volume level of the intermediate position volume control 43, fill is determined by the location of stud il in slot As shown in FIGURE 3, stud il may be adjusted as desired within a relative volume range of 5 to l0. Thus, by adjusting adjustable stud from level 5 through level 1Q, any intermediate volume position which is comfortable to the listener under normal listening conditions may be achieved. An advantage of this provision for preset intermediate volume level is that it automatically sets volume at a desired level for the listener and does this upon initial energization of television receiver 72; therefore when the user first turns on his set the hrst volume level he will hear is that of his selected intermediate position. A further increase in volume may be obtained from the intermediate position by again actuating transmitter 7d developing a command signal oi a frequency to provide a control pulse in control channsl l, thus placing ground on lead ls-fl and closing switch of bi stahle relay The driving motor then continues to increase volume until the user as l actuates transmitter 713v to develop a pulse in control channel l, opening switch ldd and de-energiring motor. The volume control steps at this position, being held there against the bias of torsion spring Z2 by means ot pawl If an annoying commercial appears on television receiver or ii the users telephone rings, it may be desired to mute the receiver directly from any attained volume setting. To this end, means are `rovitl-.ed for directly resetting volume control 43, to its mute" position. The user actuates transmitter 2li to generate a command signal of the proper frequency to develop a positive control pulse in control channel 2, thus overcoming the negative bias on grid 53 and allowing tube 37 to conduct; this grounds lead and actuates momentary-close relay 93. When switch Mfr closes, the energizing circuit to solenoid 37 is completed and solenoid 37 forces plunger 35 against bearing surface as shown in FIGURE 5. The force ot plunger 35 against bearing surface rotates rocher arm 24 in a counter-clocrrwise direction producing three results: (l) extension 33 is forced against stud 2@ of ratchet arm i7 pushing the ratchet away from the teeth of ratchet wheel ld; (2) rotation of rocker arm 24- also rotates pawl 2.3 away from the teeth of ratchet wheel l@ thereby allowing ratchet wheel i8 to rotate in a counterclockwise direction under the force of helical spring 22; and (3) hook extension 32 is moved forward into a position as shown by the solid outline in FIGURE 5 so as to intercept stud 2l of ratchet wheel lli and prevent further counter-clockwise rotation of ratchet wheel l. Since it takes a tinite amount of time for ratchet wheel lil to rotate from its original position to the position where stud 2l is intercepted by extension 32, rocker 24 must remain in the position as shown in the solid outline in FGURE 5 for a predetermined period of time. Since relay g3 is only a momentary-close relay and is only actuated a very short period of time, after switch titillopens the RC time constant of load circuit ltl, 107 keeps solenoid 37 energized at least as long as the maximum time required for ratchet wheel lil to rotate until stud 2l is intercepted by extension 32. lf plunger were allowed to return to its normal position immediately after switch opened, thus allowing rocker arm Z4 to rotate in a clockwise direction under the iniiuence ot spring Z5, both pawl Z3 and ratchet 17 would prevent any further counter-clockwise movement of ratchet wheel l@ and therefore stop any further decrease in volume.

After stud 2l is intercepted by extension 32 of rocker arrn 2d, the discharge of condenser lod continues until the plunger springs back to its normal position allowing spring 25 to pull rocker arrn in a clockwise direction. As rocker arrn 24 begins to rotate, stud 2l is freed from the extension Si, as shown by the dashed line position of the rocker arrn in 5. At this point helical spring starts t0 turn ratchet wheel lf3 in a counter-clockwise direction. rotation of ratchet wheel lla is accomplished since the release of stud 2l from extension 32 occurs before pawl Z3 intercepts a tooth of the ratchet wheel. However continued rotation of rocker arm causes pawl 23 to intercept a tooth of wheel lli before stud Ztl starts to engage projection 65, and stud il comes to res in the position shown in dashed outline 2l. in this position of the ratchet wheel, where the stud is shown by 2l', the volume level is reduced to zero and this condition is indicated in FlGUlE 3 by mute of disc il@ being located opposite index The above means for directly resetting volume control 43, 4d to its mu-te position are independent of driving means or driving motor t, rotation of rocker arm 2d in counter-clockwise direction, disengaging ratchet arm l? from contact `with the teeth of ratchet wheel allows driving lmotor to continue to rotate, thus moving the ratchet arm in a reciprocating motion hut having no eilt-:ct on the ratchet wheel.

When volume is muted and ratchet wheel lll rotates down to the mute position in a counter-clockwise direction, adiustable stud f-ll on disc momentarily engage tip portion (see FGURE 4) of switch i7 during the downward travel. However since switch i7 is normally open and this engagement just causes switch 47 to open further, 'oi-stable relay o3 to which switch 47 is connected is not tulected.

Means for fle-energizing at least a portion of television receiver includes `witch 53 which is in series with the energizing circuit to receiver power supply 93. Switch 53 is opened when the user again actuates transmitter 7d to `develop a command signal of a frequency to produce a pulse in channel 2 to close momentary-close relay S3; this energizes solenoid 37 and rotates rocker arm 24 to allow rfree movement or wheel Ratchet wheel l rotates until stud 2l engages proiection o5 to rotate plate de so that stud di dis-engages switch arm el) from contact with switch arm 5?' and thereby de-energizes receiver power supply rl'hus, control channel 2 performs two functions. Actuation of relay @E while the volume is at some 4higher level than mute results in mu ng the volume; a second actuation of relay 95 while the volume control is established in the mute position de-energizes receiver power supply 93.

Assuming that the volume is at its intermediate level,

7 with the =mechanism in the condition shown in FlGURE 4, actuation of transmitter 7d to generate a command signal yof ythe proper frequency to place ground on lead 3d closes switch lll@ of bi-stable relay S3 to energize drive motor lll and initiate volume increase. lf the volume increase is not stopped by another actuation of the transmitter Iwith consequent energization of bi-stable relay to open switch Mld, ratchet wheel lil continues to rotate. However means are provided which are responsive to establishment of volume control fc3, lli in its maximum volume or terminal position lwith switch arm contacting terminal il@ of resistance di@ for automatically de-energizing driving motor lil. Referring to FlGURE 6, as ratchet wheel l is rotated in a clockwise direction, stud 2l ultimately engages projection 65 when the volume reaches its maximum level. This rotates plate in a counter-clockwise direction and moves stud 68 against tip portion 56 t-o close switch 52.. With switch 5f?. closed, lead 8d is grounded as shown in Fifi' 3, thus energizing bi-stable relay `ts and opening switch lull to deenercize motor lil. The volume then remains at the maximum level until the user mutes volume by actuating transmitter 2dto generate a command signal of the proper frequency to develop a control pulse in control channel Z, which results in closing of switch ldd ot relay 93 and actuation of solenoid ?'7.

lf desired, further provision may be made to automatically reset the volume control to its mute position in response to the establishment of volume in its terminal position as disclosed and claimed in the copending application of Howard C. Grossenheider, Serial No. 68,213, titled Remote Control Apparatus tiled concurrently herewith.

Thus, in summary, switch 43, d4 is an adjustable volume control having a mute or reference position, an intermediate operating position, a terminal operating position and having la plurality of additional operating positions between the mute and terminal operating positions for selectively establishing a plurality of ditlerent audio output levels. Electrically operated driving means comprising driving motor l@ is coupled to the volume control 43, 44 for varying the control between its operating positions. Bi-stable relay S53 and control tube 77 are included in control channel i and are responsive to control pulses deeloped therein for energizing and de-energizing the driving motor lid at will. Control tube 37 and relays 93 and solenoid 37 are included in control channel Z and are responsive to control pulses developed therein for directly resetting volume control d3, 4d to its mute position from any other operating position.

Thus the invention provides an intelligence-reproducing apparatus, adapted -for remote control, which requires the utilization of only two control channels to give control of on-off, continuous or .innitely adjustable volume level, and instantaneous mute from any vol-urne setting.

`While a particular embodiment of the invention has been shown and described, it is apparent that modications and alterations may be made without departing from the invention in its broader aspects and therefore, the aim of t le appended claims is to cover all such modifications and alterations as fall within the true spirit and scope of the invention.

I claim:

l. Remote control apparatus comprising: a control device including an adjustable element having a reference position and a plurality of additional operating positions for controlling an operating characteristic of said apparatus; electrically operated driving means coupled to said control device for varying said adjustable element between said operating positions; control-signal-responsive means for energizing and de-energizing said driving means at will; means independent of said driving means for directly resetting said adjustable element to said reference position from any of said additional operating 8 positions; and control-signal-responsive means for actuating said resetting means.

2. Remote control apparatus comprising: a control device inoluding an adjustable element having a reference position and a plurality or" additional operating positions for controlling an operating characteristic of said apparatus; control-signal-responsive means including lirst and second control channels in which control pulses are selectively developed in response to received control .signals of predetermined lirst and second frequencies respectively; electrically operated driving means coupled to said control device for varying said adjustable element between said operating positions; means included in said rst control channel and responsive to control pulses developed therein for energizing and de-energizing said driving means at will; and means, independent of said driving means, included in said second control channel and responsive to control pulses developed therein for directly resetting said adjustable element to said reference position from any of said additional operating positions.

3. Sound reproducing apparatus adapted for Wireless remote control comprising: an adjustable volume control having a mute position and a plurality of additional operating positions for selectively establishing the audio `output level of said sound reproducing apparatus at a plurality of different sound levels; electrically operated driving lmeans coupled to said volume control for varying it between said operating positions; control-signal- Iesponsive means for energizing and cle-energizing said drivinf7 means at will; means independent of said driving means for directly resetting said volume control to said mute position from any of said additional operating positions; and control-signal-responsive means for actuating said resetting means.

4. Sound reproducing apparatus adapted for wireless remote control comprising: an adjustable volume control having a mute position for establishing the audio output level of said sound reproducing apparatus at a predetermined minimum, an intermediate operating position for establishing said output at a nominal listening level, and a plurality of additional operating positions for selectively establishing a plurality of different audio output levels; electrically operated driving means coupled to said vol-urne control for varying it between said operating positions; control-signal-responsive means for energizing and de-energizing said driving means at Will; means independent of said driving means for directly resetting said volume control to said mute position from any of said operating positions; control-signal-responsive means for actuating said resetting means; and means responsive to establishment of said volume control in said intermediate position by said driving means for de-energizing said driving means.

5. Sound reproducing apparatus according to claim 4 in which means are provided for adjusting said intermediate operating position.

6. Sound reproducing apparatus adapted for wireless remote control comprising: an adjustable volume control having a mute position for establishing the audio output level of said sound reproducing apparatus at a predetermined minimum, a terminal operating position for establishing said output at a predetermined maximum, and a plurality of additional operating positions between said mute position and said terminal operating position for selectively establishing a plurality of different audio output levels; electrically operated driving means coupled to `said volume control for varying it between said operating positions; control-signal-responsive means for energizing and cle-energizing said driving means at will; means independent of said driving means for directly resetting said volume control to said mute position trom any of said operating positions; control-signal-responsive means for actuating said resetting means; and means responsive to establishment of said volume control in said terminal position for automatically rie-energizing said driving means.

7. Sound reproducing apparatus adapted for Wireless remote control comprising: an adjustable volume control having a mute position and a plurality of additional positions for selectively establishing the audio output level of said sound reproducing apparatus at a plurality of different audio output levers; electrically operated driving means coupled to said volume control for varying it between said operating positions; control-signal-responsive means for energizing and de-energizing said driving means at will; means independent of said driving means for directly resetting said volume control to said mute position from any of said additional operating positions; control-signal-responsive means for actuating said resetting means; means for dewenergizing at least a portion of said apparatus; and means, coniointly responsive to control signals and to establishment of said volume control in said mute position, for actuating said de-energizing means.

8. Sound reproducing apparatus adapted for wireless remote control comprising: an adjustable volume control having a mute position for establishing the audio output level of said sound reproducing apparatus iat a predetermined minimum, an intermediate operating position for establishing said output at a nominal listening level, a terminal operating position for establishing said output at a predetermined maximum, and a plurality of additional operating positions between said mute position and said terminal operating position vfor selectively establishing a plurality of dillerent audio output levels; control-signalresponsive means including tirst and second control channels in which control pulses are selectively developed in response to received control signals of predetermined rst and second frequencies respectively; electrically operated driving means coupled to said volume control for varying said control between said operating positions; means included in said first control channel and responsive to control pulses developed therein for energizing and deenergizing said driving means at Will; means, independent of said driving means, included in said second control channel and responsive to control pulses eveloped therein for directly resetting said volume control to said mute lposition from any of said operating positions; means responsive to establishment of said volume control in said intermediate position by said driving means for de-energizing said driving means; means responsive to establishment of said volume control in said terminal position for cle-energizing said driving means; means for rie-energizing at least a portion of said apparatus; and means, included in said second control channel, and conjointly responsive to control pulses and to establishment of said volume control in said mute position, for actuating said die-energizing means.

9. Sound reproducing apparatus according to claim 8, in which means are provided for adjusting said intermediate operat-ing position.

References Cited in the tile of this patent UNITED STATES PATENTS 2,250,371 Grimes luly 22, 1941 2,383,338 Newman Aug. 2'1, 1945 2,817,025 Adler Dec. 17, 1957 2,330,241 Tuvok Apr. 8, 1958 2,897,354 Bourget et al lnly 28, 1959 2,923,918 Adler Feb. 2, l1960 2,947,812 Parmet et al Apr. 2, 1960 2,994,063 Gibson July 25, 1961 

1. REMOTE CONTROL APPARATUS COMPRISING: A CONTROL DEVICE INCLUDING AN ADJUSTABLE ELEMENT HAVING A REFERENCE POSITION AND A PLURALITY OF ADDITIONAL OPERATING POSITIONS FOR CONTROLLING AN OPERATING CHARACTERISTIC OF SAID APPARATUS; ELECTRICALLY OPERATED DRIVING MEANS COUPLED TO SAID CONTROL DEVICE FOR VARYING SAID ADJUSTABLE ELEMENT BETWEEN SAID OPERATING POSITIONS; CONTROL-SIGNAL-RESPONSIVE MEANS FOR ENERGIZING AND DE-ENERGIZING SAID DRIVING MEANS AT WILL; MEANS INDEPENDENT OF SAID DRIVING MEANS FOR DIRECTLY RESETTING SAID ADJUSTABLE ELEMENT TO SAID REFERENCE POSITION FROM ANY OF SAID ADDITIONAL OPERATING 